Clear cell sarcoma of the upper thoracic back muscle.

Clear cell sarcoma (CCS), also called malignant melanoma of soft parts, is a rare malignant soft tissue tumor and is often associated with tendons or aponeuroses. Most of CCS involve extremities, especially lower extremities, but a tumor occurring in the trunk is rare. We report an extremely rare case of CCS originated in the upper thoracic back muscle. To our knowledge, this case is the second report of CCS of the back muscle.